Hereditary diseases are caused by mutations in the genetic material and can be passed on to offspring without the parents themselves having the disease. The most common hereditary disease in Europe is the metabolic disorder cystic fibrosis. Around 1,000 people in Switzerland are affected.
Hereditary diseases can be caused by one or more mutations in the genetic material. But they don’t have to. It is not uncommon for the hereditary disease not to appear at all in carriers of a genetic mutation or their offspring. The reason for this is different probabilities of inheritance, recurrence and illness. Depending on the constellation, the pathogenic “inheritance” can remain hidden for several generations. In addition, there are mutations that are linked to the sex chromosome and therefore only occur in men or women.
Congenital genetic defects can lead to a loss of function, manifest themselves in dysregulated tissue growth, disrupt certain metabolic reactions or cause the death of certain cell types. As a rule, hereditary diseases cannot be cured. For certain disorders, however, the course of the disease can be slowed down by medication and a wide range of therapies.
Genetic consultation provides clarity
If you have questions about possible hereditary diseases in your family or if couples need to rule out the possibility of a hereditary disease before planning a family, a visit to the genetic consultation at the University Hospital Zurich will provide clarity. Genetic tests are used to check the chromosomes for numerical and structural changes. In the case of a genetic disease or carrier, the course of the disease, any preventive measures or special treatment strategies as well as the inheritance pattern and the risk of recurrence are explained during the consultation.
Various research projects supported by the USZ Foundation also focus on hereditary diseases. In the case of prion disease, a progressive, degenerative and previously fatal disease of the brain, researchers are looking for the genes responsible in order to create a basis for the development of drugs. Another research team is investigating genetic eye diseases. This is because the more precisely the mutation is known, the more clearly the effects on the eyes can be localized and treated in a more targeted manner in childhood.
Well-known and widespread
One of the best known hereditary diseases is color blindness (achromasia). Those affected do not perceive colors at all or only to a limited extent (di-/monochrasia). That is why they are excluded from certain professions – pilot, train driver, car painter, printing, electrical engineering. However, this illness has little impact on coping with everyday life. Around eight percent of all men have a congenital color vision disorder. For women, the figure is only 0.4 percent.
Hemophilia is an inherited and incurable disorder of blood clotting. Thanks to modern therapies, however, people with hemophilia can lead a largely normal life. For every 10,000 men, two develop hemophilia. Women are practically not affected.
Short stature (achondroplasia) is a well-known but rare hereditary disease. The length growth of the long bones is impaired in those affected. The humerus and femur are shortened in this genetic growth disorder. However, the bones are of normal thickness and the torso is almost normal in length. There is one case of achondroplasia per 20,000 births.
Far more frequently, with one case per 700 births, a child is born with Down’s syndrome (trisomy 21). This is not actually a disease, but a chromosomal anomaly. Chromosome 21 is not present twice, but three times. Affected people therefore have 47 chromosomes instead of 46. Trisomy 21 is associated with varying degrees of physical malformations and mental limitations. Depending on the individual case and individual support, however, these people can lead a largely normal life. Around 120 children with Down’s syndrome are born in Switzerland every year.
